Radiation curable coatings, such as UV/EB curable coatings, are applied to various types of substrates to enhance their durability and finish. The radiation curable coatings are typically resin based mixtures of oligomers or monomers that are cured or cross-linked after being applied to the substrate by radiation curing. The radiation curing polymerizes the resins to produce a high or low gloss coating having superior abrasion and chemical resistance properties. The radiation curable coatings of this type are often referred to as topcoats or wear layers and are used, for example, in a wide variety of flooring applications, such as on linoleum, hardwood, laminate, cork, bamboo, resilient sheet, and tile flooring.
The above-described radiation curable coatings are made from fossil fuels, such as petroleum and coal. Because the use of fossil fuels negatively impacts the environment, new radiation curable coatings need to be developed which are derived from recycled materials or renewable resources, such as biobased materials. Recycled materials are materials that have been recovered or otherwise diverted from the solid waste stream, either during the manufacturing process (pre-consumer), or after consumer use (post-consumer). Recycled materials therefore include post-industrial, as well as, post-consumer materials. Biobased materials are organic materials containing an amount of non-fossil carbon sourced from biomass, such as plants, agricultural crops, wood waste, animal waste, fats, and oils. The biobased materials formed from biomass processes therefore have a different radioactive C14 signature than those produced from fossil fuels. Because the biobased materials are organic materials containing an amount of non-fossil carbon sourced from biomass, the biobased materials may not necessarily be derived 100% from biomass. A test has therefore been established for determining the amount of biobased content in the biobased material. Generally, the amount of biobased content in the biobased material is the amount of biobased carbon in the material or product as a fraction weight (mass) or percentage weight (mass) of total organic carbon in the material or product.
The calculation of the amount of biobased content in the material or product is important for ascertaining whether the material or product, when used in commercial construction, would qualify for Leadership in Energy and Environmental Design (LEED) certification. The US Green Building Council has established a LEED rating system which sets forth scientifically based criteria for obtaining LEED certification based on a point system. As shown in Table 1, under the LEED rating system, for new construction 1 point is granted for at least 5% wt of the total of post-consumer materials and ½ post-industrial materials. A second point is granted for at least 10% wt of the total of post-consumer materials and ½ post-industrial materials. An additional point is granted for at least 5% wt of rapidly renewable building materials and products. For existing building 1 point is granted for at least 10% wt post-consumer materials. A second point is granted for at least 20% wt of post-industrial materials. An additional point is granted for at least 50% wt of rapidly renewable materials. Thus, flooring products meeting the LEED criteria can be used to obtain points for LEED certification.
TABLE 1LEED Rating SystemRatingLEED - Version 2.1RatingLEED - Version 2.0SystemNew ConstructionSystemExisting BuildingMR Credit=5% wt of post-MR Credit=10% wt of post-4.1consumer materials + ½2.1consumer materials1 Pointpost-industrial materials1 PointMR Credit=10% wt of post-MR Credit=20% wt of post-4.2consumer materials + ½2.1industrial materials1 Pointpost-industrial materials1 PointMR Credit=5% wt of rapidlyMR Credit=50% wt of rapidly6renewable building2.5renewable materials1 Pointmaterials and products1 Point
Because there has been renewed market interest in giving preference to “greener” flooring products based upon the LEED rating system, there remains a need to develop “greener” flooring products based upon existing product structures/processes and available renewable materials. The key to this approach is to integrate rapidly renewable materials, such as biobased materials, into the radiation curable coatings, such as those used in flooring applications, to reduce reliance on limited resources such as fossil fuels.